(a) Technical Field
The present disclosure relates, generally, to an integrated antenna module for a vehicle. More particularly, it relates to an antenna system that is configured to communicate with a fob in a situation where an emergency start is required, for example, in a situation where a battery of the fob is discharged.
(b) Background Art
Recently, many automobile companies are applying push button start systems to vehicles.
A considerable advantage of the push button start is to start the vehicle only with a simple push button operation, in which a start button is used as an ON/OFF switch to start the vehicle. However, many electronic devices are mounted in the vehicle, and thus OFF, ACC, IG, and START switch contacts are provided to effectively apply electrical power to these electronic devices.
In a vehicle in which the push button start system is suitably employed, the existing key box is eliminated, and thus the OFF, ACC, IG, and START powers are not suitably supplied by the switch contacts. Instead, a power control unit (e.g., smart key ECU) controls an output relay to supply electrical power based on the condition of the vehicle.
The existing mechanical key includes contacts switched by key operation. However, in the case of the push button start system, only a single push button is used to input commands. Accordingly, the push button start system includes a predetermined power logic such that an electronic control unit connected to the start button transmits a power transfer command such as OFF→ACC→IG→OFF or OFF→ACC→IG→START (when pushed together with a brake pedal) to a power distribution module (PDM) according to the order of pressing the push button and thereby the PDM supplies electrical power to an electronic steering column lock (ESCL), operates a power relay, and drives a starter motor.
During start-up, for example, when a driver carrying a fob (e.g., smart key) capable of bidirectional wireless communications approaches the vehicle, the push button start system authenticates the driver by comparing authentication information (e.g., secret code) between the vehicle and the fob. Upon completion of authentication, the electronic control unit releases the lock of the ESCL and, when the driver depressing the brake pedal pushes the start button, the PDM operates the power relay to drive the starter motor.
FIG. 1 is a block diagram showing an example of a typical button start system.
As shown in the figure, the button start system includes a power distribution module (PDM) 10, a smart key ECU 40, a start stop button (SSB) 20, an electronic steering column lock (ESCL) 30, and a fob holder 50.
The SSB 20 is a start button, which allows a driver to input a power transfer command and allows the PDM 10 to perform the power transfer according to the order of pressing the push button. The PDM 10 is a module to change the power state to ACC, IG1, IG2, cranking, and engine running (slave operation).
The smart key ECU 40 is suitably connected to the PDM 10 through a CAN communication line to provide a command to allow the PDM 10 to operate (master operation) and operates at a low frequency (LF) to locate a fob 60.
The ESCL 30 electronically controls the locking and unlocking of a steering column, and the fob holder 60 is a kind of holder in which the fob 50 is inserted to perform an immobilizer communication.
When the SSB 20 is suitably pressed in the above-described button start system, an SSB input signal is suitably input to the smart key ECU 40, and the smart key ECU 40 operates an LF antenna 42 to transmit an electromagnetic wave, thereby determining whether the fob 60 is in the interior of the vehicle.
Accordingly, the fob 60 in the interior of the vehicle responds to the wireless frequency signal transmitted from the LF antenna 42 by transmitting a signal containing authentication information. Then, the smart key ECU 40 checks the authentication information transmitted from the fob 60 to determine whether a valid fob 60 is in the interior of the vehicle.
In the case where the fob 60 is in the interior of the vehicle, the smart key ECU 40 transmits an unlock command of the steering column to the ESCL 30 and transmits a power transfer command to the PDM 10.
Accordingly, during IG ON, the smart key ECU 40 communicates with an engine management system (EMS) 70, and the EMS 70 determines an EMS running or cut by performing authentication to initiate the start-up in the event of EMS running.
Preferably, the smart key ECU 40 and the PDM 10 confirm the start-up running and then complete the power transfer.
In the button start system, in examples where the fob is carried by the driver or kept in the interior of the vehicle, when the SSB as the start button is pressed after the shift lever is shifted to the parking position (P) and the brake pedal is depressed, the engine is started through wireless communications between the fob and the smart key ECU. During shut-down of the engine, when the start button is pressed after the brake pedal is depressed and the shift lever is shifted to the parking position, the engine is shut down. Since the button start is based on the wireless communications, if a battery of the fob is discharged, it is impossible to authenticate the fob and start the engine in a normal way, and thus it is necessary to use an emergency start method.
As an emergency start method, a method in which a fob is inserted into a fob holder is widely used.
Referring to FIG. 2, according to the method in which the fob is inserted into the fob holder, the fob holder 50 is typically mounted on the right side of the steering column, and a coil antenna (i.e., immobilizer coil antenna) 51 and a demodulator (PCB) 52 connected to the PDM 10 are mounted in the fob folder 50.
Preferably, in this state, when the fob 60 is suitably inserted into the fob holder 50, a base station in the fob holder 50 suitably operates the coil antenna (i.e., immobilizer coil antenna) 51 to generate electric field and thereby electrical power is supplied to a transponder (TP) 61 mounted in the fob 60.
Preferably, then, an authentication process is performed on the fob 60 through the communication with the transponder 61 receiving the electrical power, and the base station of the fob holder 50 transmits the authentication result to the PDM 10 to permit the start-up.
In addition to the above-described emergency start method in which the fob 60 is inserted into the fob holder 50, U.S. patent application Ser. No. 10/528,148, incorporated by reference in its entirety herein, discloses an emergency engine start method in which a fob is inserted into a fob holder after opening a button cover and an authentication process is performed through an infrared (IR) communication.
In these described methods, however, the manufacturing cost is increased since the fob holder should be provided besides the start button. A failure may occur in the area where the fob is inserted and fixed to the fob holder (that is, the fob inserted into the fob holder may not be fixed to the fob holder). Moreover, after inserting the fob, the fob may not be pulled out due to damage of the fob holder.
Furthermore, it is difficult to select an appropriate position for the fob holder, and the degree of freedom is reduced in terms of vehicle design and package layout.
In addition, although the fob holder should be used for emergency purposes, the driver may frequently use the emergency start method by inserting the fob into the fob holder. The fob holder also may present issues with regards to the reliability or quality of a fob.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.